Cincinnati Financial (CINF) 10-Q 24 Apr 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 21, 2014
Document Documentand Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Trading Symbol	'CINF	'
Entity Registrant Name	'CINCINNATI FINANCIAL CORP	'
Entity Central Index Key	'0000020286	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	163,519,128

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Investments	'	'
Fixed maturities, at fair value (amortized cost: 2014—$8,609; 2013—$8,638)	$9,180	$9,121
Equity securities, at fair value (cost: 2014—$2,545; 2013—$2,523)	4,426	4,375
Other invested assets	72	68
Total investments	13,678	13,564
Cash and cash equivalents	521	433
Investment income receivable	116	121
Finance receivable	83	85
Premiums receivable	1,396	1,346
Reinsurance recoverable	546	547
Prepaid reinsurance premiums	27	26
Deferred policy acquisition costs	564	565
Land, building and equipment, net, for company use (accumulated depreciation: 2014—$424; 2013—$420)	207	210
Other assets	79	73
Separate accounts	725	692
Total assets	17,942	17,662
Insurance reserves	'	'
Loss and loss expense reserves	4,375	4,311
Life policy and investment contract reserves	2,435	2,390
Unearned premiums	2,035	1,976
Other liabilities	545	611
Deferred income tax	721	673
Note payable	104	104
Long-term debt and capital lease obligations	834	835
Separate accounts	725	692
Total liabilities	11,774	11,592
Commitments and contingent liabilities (Note 12)	0	0
Shareholders' Equity	'	'
Common stock, par value—$2 per share; (authorized: 2014 and 2013—500 million shares; issued: 2014 and 2013—198 million shares)	397	397
Paid-in capital	1,191	1,191
Retained earnings	4,287	4,268
Accumulated other comprehensive income	1,578	1,504
Treasury stock at cost (2014 and 2013—35 million shares)	-1,285	-1,290
Total shareholders' equity	6,168	6,070
Total liabilities and shareholders' equity	$17,942	$17,662

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, except Per Share data, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Fixed maturities, amortized cost	$8,609	$8,638
Equity securities, cost	2,545	2,523
Land, building and equipment, accumulated depreciation	$424	$420
Common stock, par value	$2	$2
Common stock, authorized	500	500
Common stock, issued	198	198
Common stock, outstanding	198	198
Treasury stock, shares	35	35

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Income (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Revenues	'	'
Earned premiums	$1,027	$931
Investment income, net of expenses	135	128
Realized investment gains, net	22	41
Fee revenues	3	1
Other revenues	2	2
Total revenues	1,189	1,103
Benefits and Expenses	'	'
Insurance losses and policyholder benefits	732	568
Underwriting, acquisition and insurance expenses	320	300
Interest expense	14	13
Other operating expenses	4	5
Total benefits and expenses	1,070	886
Income Before Income Taxes	119	217
Provision for Income Taxes	'	'
Current	20	54
Deferred	8	9
Total provision for income taxes	28	63
Net Income	$91	$154
Per Common Share	'	'
Net income-basic (in USD per share)	$0.56	$0.95
Net income-diluted (in USD per share)	$0.55	$0.94

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Net Income	$91	$154
Unrealized gains on investments available-for-sale, net of tax of $41 and $124, respectively	76	232
Net change in pension actuarial loss and prior service cost, net of tax of $0 and $1, respectively	-1	1
Change in life deferred acquisition costs, life policy reserves and other, net of tax of $0 and $0, respectively	-1	0
Other comprehensive income, net of tax	74	233
Comprehensive Income	$165	$387

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]	'	'
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	$41	$124
Other Comprehensive Income Loss, Pension And Other Postretirement Benefit Plans, Net Actuarial Loss And Prior Service Cost Arising During Period, Tax	0	1
Other Comprehensive Income, Change in Life Deferred Acquisition Costs, Life Policy Reserves and Other, Tax	$0	$0

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Shareholders' Equity (USD $)	Total	Common Stock	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income	Treasury Stock
In Millions
Balance at Dec. 31, 2012	$5,453	$394	$1,134	$4,021	$1,129	($1,225)
Balance (in shares) at Dec. 31, 2012	'	163	'	'	'	'
Net Income	154	'	'	154	'	'
Other comprehensive income, net	233	'	'	'	233	'
Dividends declared	-66	'	'	-66	'	'
Stock-based awards exercised and vested	'	1	'	'	'	'
Purchases	0	'	'	'	'	0
Stockholders' Equity, Other	11	'	12	'	'	-2
Balance at Mar. 31, 2013	5,785	395	1,146	4,109	1,362	-1,227
Balance (in shares) at Mar. 31, 2013	'	163	'	'	'	'
Balance at Dec. 31, 2013	6,070	397	1,191	4,268	1,504	-1,290
Balance (in shares) at Dec. 31, 2013	198	163	'	'	'	'
Net Income	91	'	'	91	'	'
Other comprehensive income, net	74	'	'	'	74	'
Dividends declared	-72	'	'	-72	'	'
Stock-based awards exercised and vested	'	0	'	'	'	'
Purchases	-7	'	'	'	'	-7
Stockholders' Equity, Other	12	'	0	'	'	12
Balance at Mar. 31, 2014	$6,168	$397	$1,191	$4,287	$1,578	($1,285)
Balance (in shares) at Mar. 31, 2014	198	163	'	'	'	'

Condensed_Consolidated_Stateme4

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Cash Flows From Operating Activities	'	'
Net Income	$91	$154
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation and amortization	13	9
Realized gains on investments, net	-22	-41
Stock-based compensation	6	5
Interest credited to contract holders	10	11
Deferred income tax expense	8	9
Changes in:	'	'
Investment income receivable	5	-2
Premiums and reinsurance receivable	-50	-82
Deferred policy acquisition costs	-5	-19
Other assets	-5	-2
Loss and loss expense reserves	64	10
Life policy reserves	49	13
Unearned premiums	59	83
Other liabilities	-102	-88
Current income tax receivable/payable	8	-3
Net cash provided by operating activities	129	57
Cash Flows From Investing Activities	'	'
Sale of fixed maturities	24	12
Call or maturity of fixed maturities	252	221
Sale of equity securities	31	98
Purchase of fixed maturities	-236	-325
Purchase of equity securities	-33	-108
Investment in finance receivables	-4	-8
Collection of finance receivables	7	7
Investment in buildings and equipment, net	-3	-1
Change in other invested assets, net	1	2
Net cash provided by (used in) investing activities	39	-102
Cash Flows From Financing Activities	'	'
Payment of cash dividends to shareholders	-67	-65
Payments for Repurchase of Common Stock	7	0
Proceeds from stock options exercised	8	6
Contract holders' funds deposited	20	24
Contract holders' funds withdrawn	-32	-31
Other	-2	4
Net cash used in financing activities	-80	-62
Net change in cash and cash equivalents	88	-107
Cash and cash equivalents at beginning of year	433	487
Cash and cash equivalents at end of period	521	380
Supplemental disclosures of cash flow information:	'	'
Interest paid	0	0
Income taxes paid	11	54
Non-cash activities:	'	'
Conversion of securities	0	43
Equipment acquired under capital lease obligations	5	12
Cashless exercise of stock options	$4	$9

Accounting_Policies

Accounting Policies	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Accounting Policies	'
	ACCOUNTING POLICIES
	The condensed consolidated financial statements include the accounts of Cincinnati Financial Corporation and its consolidated subsidiaries, each of which is wholly owned. These statements are presented in conformity with accounting principles generally accepted in the United States of America (GAAP). All intercompany balances and transactions have been eliminated in consolidation.
	The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect amounts reported in the financial statements and accompanying notes. Our actual results could differ from those estimates. Our December 31, 2013, condensed consolidated balance sheet amounts are derived from the audited financial statements but do not include all disclosures required by GAAP.
	Our March 31, 2014, condensed consolidated financial statements are unaudited. Certain financial information that is included in annual financial statements prepared in accordance with GAAP is not required for interim reporting and has been condensed or omitted. We believe that we have made all adjustments, consisting only of normal recurring accruals, that are necessary for fair presentation. These condensed consolidated financial statements should be read in conjunction with our consolidated financial statements included in our 2013 Annual Report on Form 10-K. The results of operations for interim periods do not necessarily indicate results to be expected for the full year.

Investments

Investments	3 Months Ended
	Mar. 31, 2014
Investments [Abstract]	'
Investments	'
	INVESTMENTS
	The following table provides cost or amortized cost, gross unrealized gains, gross unrealized losses and fair value for our invested assets:
	(In millions)	Cost or
		amortized			Gross unrealized					Fair
	At March 31, 2014	cost			gains			losses		value
	Fixed maturity securities:
	States, municipalities and political subdivisions	$	3,113		$	143		$	12	$	3,244
	Convertibles and bonds with warrants attached	17			—			—		17
	United States government	7			—			—		7
	Government-sponsored enterprises	211			—			20		191
	Foreign government	10			—			—		10
	Commercial mortgage-backed	206			2			2		206
	Corporate	5,045			468			8		5,505
	Subtotal	8,609			613			42		9,180
	Equity securities:
	Common equities	2,418			1,845			6		4,257
	Nonredeemable preferred equities	127			43			1		169
	Subtotal	2,545			1,888			7		4,426
	Total	$	11,154		$	2,501		$	49	$	13,606
	At December 31, 2013
	Fixed maturity securities:
	States, municipalities and political subdivisions	$	3,107		$	125		$	21	$	3,211
	Convertibles and bonds with warrants attached	17			—			—		17
	United States government	7			—			—		7
	Government-sponsored enterprises	227			—			27		200
	Foreign government	10			—			—		10
	Commercial mortgage-backed	148			—			5		143
	Corporate	5,122			433			22		5,533
	Subtotal	8,638			558			75		9,121
	Equity securities:
	Common equities	2,396			1,818			1		4,213
	Nonredeemable preferred equities	127			38			3		162
	Subtotal	2,523			1,856			4		4,375
	Total	$	11,161		$	2,414		$	79	$	13,496
	The net unrealized investment gains in our fixed-maturity portfolio are primarily the result of the continued low interest rate environment that increased the fair value of our fixed-maturity portfolio. The five largest unrealized investment gains in our common stock portfolio are from Exxon Mobil Corporation (NYSE:XOM), The Procter & Gamble Company (NYSE:PG), Honeywell International Incorporated (NYSE:HON), Chevron Corporation (NYSE:CVX), and Dover Corporation (NYSE:DOV), which had a combined gross unrealized gain of $431 million. At March 31, 2014, we had $17 million fair value of hybrid securities included in fixed maturities that follow Accounting Standards Codification (ASC) 815-15-25, Accounting for Certain Hybrid Financial Instruments, compared with $18 million fair value of hybrid securities at December 31, 2013. The hybrid securities are carried at fair value, and the changes in fair value are included in realized investment gains and losses.
	The table below provides fair values and gross unrealized losses by investment category and by the duration of the securities’ continuous unrealized loss position:
	(In millions)	Less than 12 months						12 months or more				Total		Total
		Fair			Unrealized			Fair		Unrealized		fair		unrealized
	At March 31, 2014	value			losses			value		losses		value		losses
	Fixed maturity securities:
	States, municipalities and political	$	289		$	7		$	98	$	5	$	387	$	12
	subdivisions
	United States government	11			—			—		—		11		—
	Government-sponsored enterprises	83			8			96		12		179		20
	Commercial mortgage-backed	55			1			15		1		70		2
	Corporate	291			7			65		1		356		8
	Subtotal	729			23			274		19		1,003		42
	Equity securities:
	Common equities	72			6			—		—		72		6
	Nonredeemable preferred equities	39			1			—		—		39		1
	Subtotal	111			7			—		—		111		7
	Total	$	840		$	30		$	274	$	19	$	1,114	$	49
	At December 31, 2013
	Fixed maturity securities:
	States, municipalities and political	$	490		$	18		$	42	$	3	$	532	$	21
	subdivisions
	United States government	1			—			—		—		1		—
	Government-sponsored enterprises	199			27			1		—		200		27
	Foreign government	10			—			—		—		10		—
	Commercial mortgage-backed	125			5			—		—		125		5
	Corporate	572			20			43		2		615		22
	Subtotal	1,397			70			86		5		1,483		75
	Equity securities:
Common equities	77			1			—		—		77		1
Nonredeemable preferred equities	42			3			—		—		42		3
Subtotal	119			4			—		—		119		4
Total	$	1,516		$	74		$	86	$	5	$	1,602	$	79
The following table provides investment income, realized investment gains and losses, the change in unrealized investment gains and losses, and other items:
(In millions)	Three months ended March 31,
	2014			2013
Investment income summary:
Interest on fixed maturities	$	104		$	102
Dividends on equity securities	32			27
Other investment income	1			1
Total	137			130
Less investment expenses	2			2
Total	$	135		$	128
Realized investment gains and losses summary:
Fixed maturities:
Gross realized gains	$	2		$	2
Gross realized losses	—			—
Other-than-temporary impairments	—			(2		)
Equity securities:
Gross realized gains	18			37
Gross realized losses	—			—
Other-than-temporary impairments	(1		)	—
Securities with embedded derivatives	(1		)	1
Other	4			3
Total	$	22		$	41
Change in unrealized gains and losses summary:
Fixed maturities	$	88		$	(25	)
Equity securities	29			381
Net change in pension actuarial loss and prior service cost	(1		)	2
Adjustment to deferred acquisition costs and life policy reserves	(3		)	3
Other	2			(3		)
Income taxes on above	(41		)	(125		)
Total	$	74		$	233
During the three months ended March 31, 2014 and 2013, there were no credit losses on fixed-maturity securities for which a portion of other-than-temporary impairment (OTTI) has been recognized in other comprehensive income.
During the quarter ended March 31, 2014, there were two equity securities and one fixed-maturity security other-than-temporarily impaired. At March 31, 2014, ninety-nine fixed-maturity investments with a total unrealized loss of $19 million had been in an unrealized loss position for 12 months or more. Of that total, no fixed-maturity investments had fair values below 70 percent of amortized cost. One equity investment with a total unrealized loss of less than $500,000 had been in an unrealized loss position for 12 months or more as of March 31, 2014. This equity investment was not trading below 70 percent of cost.
During 2013, we other-than-temporarily impaired seven fixed-maturity securities. At December 31, 2013, forty fixed-maturity investments with a total unrealized loss of $5 million had been in an unrealized loss position for 12 months or more. Of that total, no fixed-maturity investments had fair values below 70 percent of amortized cost. There were no equity investments in an unrealized loss position for 12 months or more as of December 31, 2013.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	FAIR VALUE MEASUREMENTS
	Fair Value Hierarchy
	In accordance with accounting guidance for fair value measurements and disclosures, we categorized our financial instruments, based on the priority of the observable and market-based data for the valuation technique used, into a three-level fair value hierarchy. The fair value hierarchy gives the highest priority to quoted prices with readily available independent data in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable market inputs (Level 3). When various inputs for measurement fall within different levels of the fair value hierarchy, the lowest observable input that has a significant impact on fair value measurement is used. Our valuation techniques have not changed from those used at December 31, 2013, and ultimately management determines fair value. See our 2013 Annual Report on Form 10-K, Item 8, Note 3, Fair Value Measurements, Page 121, for information on characteristics and valuation techniques used in determining fair value.
	Fair Value Disclosures for Assets
	The following tables illustrate the fair value hierarchy for those assets measured at fair value on a recurring basis at March 31, 2014, and December 31, 2013. We do not have any material liabilities carried at fair value. There were no transfers between Level 1 and Level 2.
	(In millions)		Quoted prices in			Significant other			Significant			Total
			active markets for			observable inputs			unobservable
			identical assets			(Level 2)			inputs
	At March 31, 2014		(Level 1)						(Level 3)
	Fixed maturities, available for sale:
	States, municipalities and political subdivisions		$	—		$	3,244		$	—		$	3,244
	Convertibles and bonds with warrants attached		—			17			—			17
	United States government		7			—			—			7
	Government-sponsored enterprises		—			191			—			191
	Foreign government		—			10			—			10
	Commercial mortgage-backed		—			201			5			206
	Corporate		—			5,497			8			5,505
	Subtotal		7			9,160			13			9,180
	Common equities, available for sale		4,257			—			—			4,257
	Nonredeemable preferred equities, available for sale		—			167			2			169
	Separate accounts taxable fixed maturities		—			700			—			700
	Top Hat Savings Plan mutual funds and common equity (included in Other assets)		17			—			—			17
	Total		$	4,281		$	10,027		$	15		$	14,323
	At December 31, 2013
	Fixed maturities, available for sale:
	States, municipalities and political subdivisions		$	—		$	3,211		$	—		$	3,211
	Convertibles and bonds with warrants attached		—			17			—			17
	United States government		7			—			—			7
	Government-sponsored enterprises		—			200			—			200
	Foreign government		—			10			—			10
	Commercial mortgage-backed		—			143			—			143
	Corporate		—			5,531			2			5,533
	Subtotal		7			9,112			2			9,121
	Common equities, available for sale		4,213			—			—			4,213
	Nonredeemable preferred equities, available for sale		—			160			2			162
	Separate accounts taxable fixed-maturities		—			682			—			682
	Top Hat Savings Plan mutual funds and common equity (included in Other assets)		14			—			—			14
	Total		$	4,234		$	9,954		$	4		$	14,192
	Each financial instrument that was deemed to have significant unobservable inputs when determining valuation is identified in the following tables by security type with a summary of changes in fair value as of March 31, 2014. Total Level 3 assets continue to be less than 1 percent of financial assets measured at fair value in the condensed consolidated balance sheets. Assets presented in the table below were valued based primarily on broker/dealer quotes for which there is a lack of transparency as to inputs used to develop the valuations. The quantitative detail of these unobservable inputs is neither provided nor reasonably available to us.
	The following tables provide the change in Level 3 assets for the three months ended March 31:
	(In millions)	Asset fair value measurements using significant unobservable inputs (Level 3)
			Corporate			Commercial			States,			Nonredeemable preferred			Total
			fixed			mortgage-			municipalities			equities
			maturities			backed fixed maturities			and political
									subdivisions
									fixed maturities
	Beginning balance, January 1, 2014		$	2		$	—		$	—		$	2		$	4
	Total gains or losses (realized/unrealized):
	Included in net income		—			—			—			—			—
	Included in other comprehensive income		—			—			—			—			—
	Purchases		—			—			—			—			—
	Sales		—			—			—			—			—
	Transfers into Level 3		6			5			—			—			11
	Transfers out of Level 3		—			—			—			—			—
	Ending balance, March 31, 2014		$	8		$	5		$	—		$	2		$	15
	Beginning balance, January 1, 2013		$	3		$	—		$	1		$	1		$	5
	Total gains or losses (realized/unrealized):
	Included in net income		—			—			—			—			—
	Included in other comprehensive income		—			—			—			—			—
	Purchases		—			—			—			1			1
	Sales		—			—			—			—			—
	Transfers into Level 3		—			—			—			—			—
	Transfers out of Level 3		—			—			—			—			—
Ending balance, March 31, 2013		$	3		$	—		$	1		$	2		$	6
Additional disclosures for the Level 3 category are not material.
Fair Value Disclosure for Assets and Liabilities Not Carried at Fair Value
The disclosures below are presented to provide timely information about the effects of current market conditions on financial instruments that are not reported at fair value in our condensed consolidated financial statements.
This table summarizes the book value and principal amounts of our long-term debt:
(In millions)						Book value						Principal amount
						March 31,			December 31,			March 31,			December 31,
Interest rate			Year of issue			2014			2013			2014			2013
6.9	%		1998	Senior debentures, due 2028		$	28		$	28		$	28		$	28
6.92	%		2005	Senior debentures, due 2028		391			391			391			391
6.125	%		2004	Senior notes, due 2034		371			371			374			374
				Total		$	790		$	790		$	793		$	793
The following table shows fair values of our note payable and long-term debt subject to fair value disclosure requirements:
(In millions)		Quoted prices in			Significant other			Significant			Total
		active markets for			observable inputs			unobservable
		identical assets			(Level 2)			inputs
At March 31, 2014		(Level 1)						(Level 3)
Note payable		$	—		$	104		$	—		$	104
6.900% senior debentures, due 2028		—			32			—			32
6.920% senior debentures, due 2028		—			470			—			470
6.125% senior notes, due 2034		—			419			—			419
Total		$	—		$	1,025		$	—		$	1,025
At December 31, 2013
Note payable		$	—		$	104		$	—		$	104
6.900% senior debentures, due 2028		—			30			—			30
6.920% senior debentures, due 2028		—			458			—			458
6.125% senior notes, due 2034		—			399			—			399
Total		$	—		$	991		$	—		$	991
The following table shows the fair value of our life policy loans, included in other invested assets, subject to fair value disclosure requirements:
(In millions)		Quoted prices in			Significant other			Significant			Total
		active markets for			observable inputs			unobservable
		identical assets			(Level 2)			inputs
At March 31, 2014		(Level 1)						(Level 3)
Life policy loans		$	—		$	—		$	44		$	44
At December 31, 2013
Life policy loans		$	—		$	—		$	45		$	45
Outstanding principal and interest for these life policy loans was $35 million and $36 million at March 31, 2014, and December 31, 2013, respectively.
The following table shows fair values of our deferred annuities and structured settlements, included in life policy and investment contract reserves, subject to fair value disclosure requirements:
(In millions)		Quoted prices in			Significant other			Significant			Total
		active markets for			observable inputs			unobservable
		identical assets			(Level 2)			inputs
At March 31, 2014		(Level 1)						(Level 3)
Deferred annuities		$	—		$	—		$	900		$	900
Structured settlements		—			212			—			212
Total		$	—		$	212		$	900		$	1,112
At December 31, 2013
Deferred annuities		$	—		$	—		$	911		$	911
Structured settlements		—			219			—			219
Total		$	—		$	219		$	911		$	1,130
Recorded reserves for the deferred annuities and structured settlements were $1.051 billion at March 31, 2014, and December 31, 2013.

Property_Casualty_Loss_and_Los

Property Casualty Loss and Loss Expenses	3 Months Ended
	Mar. 31, 2014
Premiums Written, Net [Abstract]	'
Property Casualty Loss And Loss Expenses	'
	PROPERTY CASUALTY LOSS AND LOSS EXPENSES
	This table summarizes activity for our consolidated property casualty loss and loss expense reserves:
	(In millions)	Three months ended March 31,
		2014			2013
	Gross loss and loss expense reserves, beginning of period	$	4,241		$	4,169
	Less reinsurance receivable	299			356
	Net loss and loss expense reserves, beginning of period	3,942			3,813
	Net incurred loss and loss expenses related to:
	Current accident year	705			534
	Prior accident years	(29		)	(10		)
	Total incurred	676			524
	Net paid loss and loss expenses related to:
	Current accident year	197			121
	Prior accident years	387			392
	Total paid	584			513
	Net loss and loss expense reserves, end of period	4,034			3,824
	Plus reinsurance receivable	289			349
	Gross loss and loss expense reserves, end of period	$	4,323		$	4,173
	We use actuarial methods, models and judgment to estimate, as of a financial statement date, the property casualty loss and loss expense reserves required to pay for and settle all outstanding insured claims, including incurred but not reported (IBNR) claims, as of that date. The actuarial estimate is subject to review and adjustment by an
	inter-departmental committee that includes actuarial management that is familiar with relevant company and industry business, claims and underwriting trends, as well as general economic and legal trends that could affect future loss and loss expense payments. The amount we will actually have to pay for claims can be highly uncertain. This uncertainty, together with the size of our reserves, makes the loss and loss expense reserves our most significant estimate. The reserve for loss and loss expenses in the condensed consolidated balance sheets also included $52 million at March 31, 2014, and $67 million at March 31, 2013, for certain life and health loss and loss expense reserves.
	For the three months ended March 31, 2014, we experienced $29 million of favorable development on prior accident years, including $3 million of favorable development in commercial lines, $17 million of favorable development in personal lines and $9 million favorable development in excess and surplus lines. This included
	$9 million from favorable development of catastrophe losses for the three months ended March 31, 2014, compared with $7 million of favorable development of catastrophe losses for the three months ended March 31, 2013.

Life_Policy_and_Investment_Con

Life Policy and Investment Contract Reserves	3 Months Ended
	Mar. 31, 2014
Liability for Future Policy Benefits [Abstract]	'
Life Policy And Investment Contract Reserves	'
	LIFE POLICY AND INVESTMENT CONTRACT RESERVES
	We establish the reserves for traditional life insurance policies based on expected expenses, mortality, morbidity, withdrawal rates, timing of claim presentation and investment yields, including a provision for uncertainty. Once these assumptions are established, they generally are maintained throughout the lives of the contracts. We use both our own experience and industry experience, adjusted for historical trends, in arriving at our assumptions for expected mortality, morbidity and withdrawal rates as well as for expected expenses. We base our assumptions for expected investment income on our own experience adjusted for current economic conditions.
	We establish reserves for the company’s universal life, deferred annuity and structured settlement policies equal to the cumulative account balances, which include premium deposits plus credited interest less charges and withdrawals. Some of our universal life policies contain no-lapse guarantee provisions. For these policies, we establish a reserve in addition to the account balance, based on expected no-lapse guarantee benefits and expected policy assessments.
	This table summarizes our life policy and investment contract reserves:
	(In millions)	March 31,		December 31, 2013
		2014
	Ordinary/traditional life	$	830	$	815
	Universal life	509		508
	Deferred annuities	864		862
	Structured settlements	187		189
	Other	45		16
	Total life policy and investment contract reserves	$	2,435	$	2,390

Deferred_Acquisition_Costs

Deferred Acquisition Costs	3 Months Ended
	Mar. 31, 2014
Deferred Costs [Abstract]	'
Deferred Acquisition Costs	'
	DEFERRED ACQUISITION COSTS
	Expenses directly related to successfully acquiring insurance policies – primarily commissions, premium taxes and underwriting costs – are deferred and amortized over the terms of the policies. We update our acquisition cost assumptions periodically to reflect actual experience, and we evaluate the costs for recoverability. The table below shows the deferred policy acquisition costs and asset reconciliation.
	(In millions)	Three months ended March 31,
		2014			2013
	Deferred policy acquisition costs asset, beginning of period	$	565		$	470
	Capitalized deferred policy acquisition costs	206			198
	Amortized deferred policy acquisition costs	(201		)	(179		)
	Amortized shadow deferred policy acquisition costs	(6		)	2
	Deferred policy acquisition costs asset, end of period	$	564		$	491
	No premium deficiencies were recorded in the condensed consolidated statements of income, as the sum of the anticipated loss and loss adjustment expenses, policyholder dividends and unamortized deferred acquisition expenses did not exceed the related unearned premiums and anticipated investment income.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	3 Months Ended
	Mar. 31, 2014
Accumulated Other Comprehensive Income [Abstract]	'
Comprehensive Income (Loss) Note	'
	ACCUMULATED OTHER COMPREHENSIVE INCOME
	Accumulated other comprehensive income includes changes in unrealized gains and losses on available for sale investments and other invested assets, changes in pension obligations and changes in life deferred acquisition costs, life policy reserves and other as follows:
	(In millions)	Three months ended March 31,
		2014									2013
		Before tax			Income tax			Net			Before tax			Income tax			Net
	Accumulated unrealized gains, net, on investments available for sale,	$	2,335		$	808		$	1,527		$	1,875		$	647		$	1,228
	beginning of period
	Other comprehensive income before reclassification	135			48			87			397			139			258
	Reclassification adjustment for realized investment gains, net,	(18		)	(7		)	(11		)	(41		)	(15		)	(26		)
	included in net income
	Effect on other comprehensive income	117			41			76			356			124			232
	Accumulated unrealized gains, net, on investments available for sale,	$	2,452		$	849		$	1,603		$	2,231		$	771		$	1,460
	end of period
	Accumulated unrealized losses, net, for pension obligations,	$	(18	)	$	(6	)	$	(12	)	$	(101	)	$	(35	)	$	(66	)
	beginning of period
	Effect on other comprehensive income	(1		)	—			(1		)	2			1			1
	Accumulated unrealized losses, net, for pension obligations,	$	(19	)	$	(6	)	$	(13	)	$	(99	)	$	(34	)	$	(65	)
	end of period
	Accumulated unrealized losses, net, on life deferred acquisition costs,	$	(16	)	$	(5	)	$	(11	)	$	(50	)	$	(17	)	$	(33	)
	life policy reserves and other, beginning of period
	Other comprehensive income before reclassification	3			1			2			—			—			—
	Reclassification adjustment for life deferred acquisition costs,	(4		)	(1		)	(3		)	—			—			—
	life policy reserves and other, net, included in net income
	Effect on other comprehensive income	(1		)	—			(1		)	—			—			—
	Accumulated unrealized losses, net, on life deferred acquisition costs,	$	(17	)	$	(5	)	$	(12	)	$	(50	)	$	(17	)	$	(33	)
	life policy reserves and other, end of period
	Accumulated other comprehensive income, beginning of period	$	2,301		$	797		$	1,504		$	1,724		$	595		$	1,129
	Change in unrealized gains, net, on investments available for sale	117			41			76			356			124			232
	Change in pension obligations	(1		)	—			(1		)	2			1			1
	Change in life deferred acquisition costs, life policy reserves	(1		)	—			(1		)	—			—			—
	and other
	Effect on other comprehensive income	115			41			74			358			125			233
	Accumulated other comprehensive income, end of period	$	2,416		$	838		$	1,578		$	2,082		$	720		$	1,362
	The reclassification adjustment for realized gains on investments available for sale and life deferred acquisition costs, life policy reserves and other is recorded in the total realized investment gains, net, line item of the condensed consolidated statements of income.

Reinsurance

Reinsurance	3 Months Ended
	Mar. 31, 2014
Reinsurance Disclosures [Abstract]	'
Reinsurance	'
	REINSURANCE
	Reinsurance mitigates the risk of highly uncertain exposures and limits the maximum net loss that can arise from large risks or risks concentrated in areas of exposure. Management's decisions about the appropriate level of risk retention are affected by various factors, including changes in our underwriting practices, capacity to retain risks and reinsurance market conditions.
	Primary components of our property casualty reinsurance program include a property per risk treaty, property excess treaty, casualty per occurrence treaty, casualty excess treaty, property catastrophe treaty and catastrophe bonds.
	Our condensed consolidated statements of income include earned consolidated property casualty insurance premiums on assumed and ceded business:
	(In millions)	Three months ended March 31,
		2014			2013
	Direct earned premiums	$	1,019		$	935
	Assumed earned premiums	3			2
	Ceded earned premiums	(43		)	(48		)
	Net earned premiums	$	979		$	889
	Our condensed consolidated statements of income include incurred consolidated property casualty insurance loss and loss expenses on assumed and ceded business:
	(In millions)	Three months ended March 31,
		2014			2013
	Direct incurred loss and loss expenses	$	677		$	535
	Assumed incurred loss and loss expenses	2			2
	Ceded incurred loss and loss expenses	(3		)	(13		)
	Net incurred loss and loss expenses	$	676		$	524
	Our life insurance company purchases reinsurance for protection of a portion of the risk that is written. Primary components of our life reinsurance program include individual mortality coverage and aggregate catastrophe and accidental death coverage in excess of certain deductibles.
	Our condensed consolidated statements of income include earned life insurance premiums on ceded business:
	(In millions)	Three months ended March 31,
		2014			2013
	Direct earned premiums	$	62		$	56
	Ceded earned premiums	(14		)	(14		)
	Net earned premiums	$	48		$	42
	Our condensed consolidated statements of income include life insurance policyholders’ benefits incurred on ceded business:
	(In millions)	Three months ended March 31,
		2014			2013
	Direct policyholders' benefits incurred	$	80		$	64
	Ceded policyholders' benefits incurred	(24		)	(20		)
	Net policyholders' benefits incurred	$	56		$	44
	The ceded benefits incurred can vary depending on the type of life insurance policy held and the year the policy was sold.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	INCOME TAXES
	As of March 31, 2014, and December 31, 2013, we had no liability for unrecognized tax benefits.
	The differences between the 35 percent statutory income tax rate and our effective income tax rate were as follows:
	(In millions)	Three months ended March 31,
		2014					2013
	Tax at statutory rate	$	42		35	%	$	76		35	%
	Increase (decrease) resulting from:
	Tax-exempt income from municipal bonds	(8		)	(6.7	)	(8		)	(3.7	)
	Dividend received exclusion	(7		)	(5.9	)	(6		)	(2.6	)
	Other	1			1.1		1			0.3
	Provision for income taxes	$	28		23.5	%	$	63		29	%
	The change in our effective tax rate was primarily due to changes in pretax income from underwriting results and realized investment gains and losses, compared with unchanged levels of permanent book-tax differences.

Net_Income_Per_Common_Share

Net Income Per Common Share	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Net Income Per Common Share	'
	NET INCOME PER COMMON SHARE
	Basic earnings per share are computed based on the weighted average number of common shares outstanding. Diluted earnings per share are computed based on the weighted average number of common and dilutive potential common shares outstanding using the treasury stock method. The table shows calculations for basic and diluted earnings per share:
	(In millions except per share data)	Three months ended March 31,
		2014		2013
	Numerator:
	Net income—basic and diluted	$	91	$	154
	Denominator:
	Basic weighted-average common shares outstanding	163.4		163.1
	Effect of stock-based awards:
	Stock options	1		1
	Nonvested shares	0.6		0.8
	Adjusted diluted weighted-average shares	165		164.9
	Earnings per share:
	Basic	$	0.56	$	0.95
	Diluted	0.55		0.94
	Number of anti-dilutive stock-based awards	0.7		2.1
	The sources of dilution of our common shares are certain equity-based awards. See our 2013 Annual Report on Form 10-K, Item 8, Note 17, Share-Based Associate Compensation Plans, Page 154, for information about equity-based awards. The above table shows the number of anti-dilutive stock-based awards for the three months ended March 31, 2014 and 2013. We did not include these stock-based awards in the computation of net income per common share (diluted) because their exercise would have anti-dilutive effects.

Employee_Retirement_Benefits

Employee Retirement Benefits	3 Months Ended
	Mar. 31, 2014
Compensation and Retirement Disclosure [Abstract]	'
Employee Retirement Benefits	'
	EMPLOYEE RETIREMENT BENEFITS
	The following summarizes the components of net periodic costs for our qualified and supplemental pension plans:
	(In millions)	Three months ended March 31,
		2014			2013
	Service cost	$	2		$	3
	Interest cost	4			3
	Expected return on plan assets	(4		)	(4		)
	Amortization of actuarial loss and prior service cost	1			2
	Net periodic benefit cost	$	3		$	4
	See our 2013 Annual Report on Form 10-K, Item 8, Note 13, Employee Retirement Benefits, Page 148, for information on our retirement benefits. We made matching contributions of $4 million and $3 million to our
	401(k) and Top Hat savings plans during the first quarters of 2014 and 2013.
	We contributed $5 million to our qualified pension plan during the first quarter of 2014. We do not anticipate further contributions to our qualified pension plan during the remainder of 2014.

Commitments_and_Contingent_Lia

Commitments and Contingent Liabilities	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments And Contingent Liabilities	'
	COMMITMENTS AND CONTINGENT LIABILITIES
	In the ordinary course of conducting business, the company and its subsidiaries are named as defendants in various legal proceedings. Most of these proceedings are claims litigation involving the company's insurance subsidiaries in which the company is either defending or providing indemnity for third-party claims brought against insureds or litigating first-party coverage claims. The company accounts for such activity through the establishment of unpaid loss and loss adjustment expense reserves. We believe that the ultimate liability, if any, with respect to such ordinary-course claims litigation, after consideration of provisions made for potential losses and costs of defense, is immaterial to our consolidated financial condition, results of operations and cash flows.
	The company and its subsidiaries also are occasionally involved in other legal and regulatory proceedings, some of which assert claims for substantial amounts. These actions include, among others, putative class actions seeking certification of a state or national class. Such proceedings have alleged, for example, breach of an alleged duty to search national data bases to ascertain unreported deaths of insureds under life insurance policies. The company's insurance subsidiaries also are occasionally parties to individual actions in which extra-contractual damages, punitive damages or penalties are sought, such as claims alleging bad faith handling of insurance claims or writing unauthorized coverage or claims alleging discrimination by former associates.
	On a quarterly basis, we review these outstanding matters. Under current accounting guidance, we establish accruals when it is probable that a loss has been incurred and we can reasonably estimate its potential exposure. The company accounts for such probable and estimable losses, if any, through the establishment of legal expense reserves. Based on our quarterly review, we believe that our accruals for probable and estimable losses are reasonable and that the amounts accrued do not have a material effect on our consolidated financial condition or results of operations. However, if any one or more of these matters results in a judgment against us or settlement for an amount that is significantly greater than the amount accrued, the resulting liability could have a material effect on the company's consolidated results of operations or cash flows. Based on our most recent review, our estimate for any other matters for which the risk of loss is not probable, but more than remote, is less than $1 million.

Segment_Information

Segment Information	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segment Information	'
	SEGMENT INFORMATION
	We operate primarily in two industries, property casualty insurance and life insurance. We regularly review our reporting segments to make decisions about allocating resources and assessing performance:
	•	Commercial lines property casualty insurance
	•	Personal lines property casualty insurance
	•	Excess and surplus lines property casualty insurance
	•	Life insurance
	•	Investments
	We report as Other the noninvestment operations of the parent company and its noninsurer subsidiary, CFC Investment Company. See our 2013 Annual Report on Form 10-K, Item 8, Note 18, Segment Information, Page 156, for a description of revenue, income or loss before income taxes and identifiable assets for each of the five segments.
	Segment information is summarized in the following table:
	(In millions)		Three months ended March 31,
			2014			2013
	Revenues:
	Commercial lines insurance
	Commercial casualty		$	224		$	204
	Commercial property		171			147
	Commercial auto		126			114
	Workers' compensation		92			88
	Specialty packages		36			39
	Management liability and surety		31			29
	Machinery and equipment		12			10
	Commercial lines insurance premiums		692			631
	Fee revenue		1			—
	Total commercial lines insurance		693			631
	Personal lines insurance
	Personal auto		116			107
	Homeowner		109			96
	Other personal lines		29			28
	Personal lines insurance premiums		254			231
	Excess and surplus lines insurance		33			27
	Life insurance premiums		48			42
	Separate account investment management fees		2			1
	Total life insurance		50			43
	Investment operations
	Investment income, net of expenses		135			128
	Realized investment gains, net		22			41
	Total investment revenue		157			169
	Other		2			2
	Total revenues		$	1,189		$	1,103
	Income (loss) before income taxes:
	Insurance underwriting results
	Commercial lines insurance		$	2		$	58
	Personal lines insurance		(7		)	20
	Excess and surplus lines insurance		4			—
	Life insurance		—			7
	Investment operations		136			148
	Other		(16		)	(16		)
	Total income before income taxes		$	119		$	217
	Identifiable assets:		March 31,			December 31, 2013
			2014
	Property casualty insurance		$	2,493		$	2,455
	Life insurance		1,302			1,225
	Investment operations		13,730			13,618
	Other		417			364
	Total		$	17,942		$	17,662

Investments_Tables

Investments (Tables)	3 Months Ended
	Mar. 31, 2014
Investments [Abstract]	'
Analysis Of Cost Or Amortized Cost, Gross Unrealized Gains And Losses And Fair Value for Investments	'
	The following table provides cost or amortized cost, gross unrealized gains, gross unrealized losses and fair value for our invested assets:
	(In millions)	Cost or
		amortized			Gross unrealized					Fair
	At March 31, 2014	cost			gains			losses		value
	Fixed maturity securities:
	States, municipalities and political subdivisions	$	3,113		$	143		$	12	$	3,244
	Convertibles and bonds with warrants attached	17			—			—		17
	United States government	7			—			—		7
	Government-sponsored enterprises	211			—			20		191
	Foreign government	10			—			—		10
	Commercial mortgage-backed	206			2			2		206
	Corporate	5,045			468			8		5,505
	Subtotal	8,609			613			42		9,180
	Equity securities:
	Common equities	2,418			1,845			6		4,257
	Nonredeemable preferred equities	127			43			1		169
	Subtotal	2,545			1,888			7		4,426
	Total	$	11,154		$	2,501		$	49	$	13,606
	At December 31, 2013
	Fixed maturity securities:
	States, municipalities and political subdivisions	$	3,107		$	125		$	21	$	3,211
	Convertibles and bonds with warrants attached	17			—			—		17
	United States government	7			—			—		7
	Government-sponsored enterprises	227			—			27		200
	Foreign government	10			—			—		10
	Commercial mortgage-backed	148			—			5		143
	Corporate	5,122			433			22		5,533
	Subtotal	8,638			558			75		9,121
	Equity securities:
	Common equities	2,396			1,818			1		4,213
	Nonredeemable preferred equities	127			38			3		162
	Subtotal	2,523			1,856			4		4,375
	Total	$	11,161		$	2,414		$	79	$	13,496
Fair Values And Unrealized Losses by Investment Category And By The Duration Of The Securities' Continuous Unrealized Loss Position	'
	The table below provides fair values and gross unrealized losses by investment category and by the duration of the securities’ continuous unrealized loss position:
	(In millions)	Less than 12 months						12 months or more				Total		Total
		Fair			Unrealized			Fair		Unrealized		fair		unrealized
	At March 31, 2014	value			losses			value		losses		value		losses
	Fixed maturity securities:
	States, municipalities and political	$	289		$	7		$	98	$	5	$	387	$	12
	subdivisions
	United States government	11			—			—		—		11		—
	Government-sponsored enterprises	83			8			96		12		179		20
	Commercial mortgage-backed	55			1			15		1		70		2
	Corporate	291			7			65		1		356		8
	Subtotal	729			23			274		19		1,003		42
	Equity securities:
	Common equities	72			6			—		—		72		6
	Nonredeemable preferred equities	39			1			—		—		39		1
	Subtotal	111			7			—		—		111		7
	Total	$	840		$	30		$	274	$	19	$	1,114	$	49
	At December 31, 2013
	Fixed maturity securities:
	States, municipalities and political	$	490		$	18		$	42	$	3	$	532	$	21
	subdivisions
	United States government	1			—			—		—		1		—
	Government-sponsored enterprises	199			27			1		—		200		27
	Foreign government	10			—			—		—		10		—
	Commercial mortgage-backed	125			5			—		—		125		5
	Corporate	572			20			43		2		615		22
	Subtotal	1,397			70			86		5		1,483		75
	Equity securities:
	Common equities	77			1			—		—		77		1
	Nonredeemable preferred equities	42			3			—		—		42		3
	Subtotal	119			4			—		—		119		4
	Total	$	1,516		$	74		$	86	$	5	$	1,602	$	79
Investment Income, Realized Investment Gains And Losses And Change In Unrealized Investment Gains And Losses	'
	The following table provides investment income, realized investment gains and losses, the change in unrealized investment gains and losses, and other items:
	(In millions)	Three months ended March 31,
		2014			2013
	Investment income summary:
	Interest on fixed maturities	$	104		$	102
	Dividends on equity securities	32			27
	Other investment income	1			1
	Total	137			130
	Less investment expenses	2			2
	Total	$	135		$	128
	Realized investment gains and losses summary:
	Fixed maturities:
	Gross realized gains	$	2		$	2
	Gross realized losses	—			—
	Other-than-temporary impairments	—			(2		)
	Equity securities:
	Gross realized gains	18			37
	Gross realized losses	—			—
	Other-than-temporary impairments	(1		)	—
	Securities with embedded derivatives	(1		)	1
	Other	4			3
	Total	$	22		$	41
	Change in unrealized gains and losses summary:
	Fixed maturities	$	88		$	(25	)
	Equity securities	29			381
	Net change in pension actuarial loss and prior service cost	(1		)	2
	Adjustment to deferred acquisition costs and life policy reserves	(3		)	3
	Other	2			(3		)
	Income taxes on above	(41		)	(125		)
	Total	$	74		$	233

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'
Fair Value Hierarchy for Assets Measured at Fair Value on a Recurring Basis	'
	The following tables illustrate the fair value hierarchy for those assets measured at fair value on a recurring basis at March 31, 2014, and December 31, 2013. We do not have any material liabilities carried at fair value. There were no transfers between Level 1 and Level 2.
	(In millions)		Quoted prices in			Significant other			Significant			Total
			active markets for			observable inputs			unobservable
			identical assets			(Level 2)			inputs
	At March 31, 2014		(Level 1)						(Level 3)
	Fixed maturities, available for sale:
	States, municipalities and political subdivisions		$	—		$	3,244		$	—		$	3,244
	Convertibles and bonds with warrants attached		—			17			—			17
	United States government		7			—			—			7
	Government-sponsored enterprises		—			191			—			191
	Foreign government		—			10			—			10
	Commercial mortgage-backed		—			201			5			206
	Corporate		—			5,497			8			5,505
	Subtotal		7			9,160			13			9,180
	Common equities, available for sale		4,257			—			—			4,257
	Nonredeemable preferred equities, available for sale		—			167			2			169
	Separate accounts taxable fixed maturities		—			700			—			700
	Top Hat Savings Plan mutual funds and common equity (included in Other assets)		17			—			—			17
	Total		$	4,281		$	10,027		$	15		$	14,323
	At December 31, 2013
	Fixed maturities, available for sale:
	States, municipalities and political subdivisions		$	—		$	3,211		$	—		$	3,211
	Convertibles and bonds with warrants attached		—			17			—			17
	United States government		7			—			—			7
	Government-sponsored enterprises		—			200			—			200
	Foreign government		—			10			—			10
	Commercial mortgage-backed		—			143			—			143
	Corporate		—			5,531			2			5,533
	Subtotal		7			9,112			2			9,121
	Common equities, available for sale		4,213			—			—			4,213
	Nonredeemable preferred equities, available for sale		—			160			2			162
	Separate accounts taxable fixed-maturities		—			682			—			682
	Top Hat Savings Plan mutual funds and common equity (included in Other assets)		14			—			—			14
	Total		$	4,234		$	9,954		$	4		$	14,192
Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)	'
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block]	'
	This table summarizes the book value and principal amounts of our long-term debt:
	(In millions)						Book value						Principal amount
							March 31,			December 31,			March 31,		December 31,
	Interest rate			Year of issue			2014			2013			2014		2013
	6.9	%		1998	Senior debentures, due 2028		$	28		$	28		$	28	$	28
	6.92	%		2005	Senior debentures, due 2028		391			391			391		391
	6.125	%		2004	Senior notes, due 2034		371			371			374		374
					Total		$	790		$	790		$	793	$	793
Fair Value of Life Policy Loans	'
	The following table shows the fair value of our life policy loans, included in other invested assets, subject to fair value disclosure requirements:
	(In millions)		Quoted prices in			Significant other			Significant			Total
			active markets for			observable inputs			unobservable
			identical assets			(Level 2)			inputs
	At March 31, 2014		(Level 1)						(Level 3)
	Life policy loans		$	—		$	—		$	44		$	44
	At December 31, 2013
	Life policy loans		$	—		$	—		$	45		$	45
Debt	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'
Fair Values of Deferred Annuities, Structured Settlements and Other Items	'
	The following table shows fair values of our note payable and long-term debt subject to fair value disclosure requirements:
	(In millions)		Quoted prices in			Significant other			Significant			Total
			active markets for			observable inputs			unobservable
			identical assets			(Level 2)			inputs
	At March 31, 2014		(Level 1)						(Level 3)
	Note payable		$	—		$	104		$	—		$	104
	6.900% senior debentures, due 2028		—			32			—			32
	6.920% senior debentures, due 2028		—			470			—			470
	6.125% senior notes, due 2034		—			419			—			419
	Total		$	—		$	1,025		$	—		$	1,025
	At December 31, 2013
	Note payable		$	—		$	104		$	—		$	104
	6.900% senior debentures, due 2028		—			30			—			30
	6.920% senior debentures, due 2028		—			458			—			458
	6.125% senior notes, due 2034		—			399			—			399
	Total		$	—		$	991		$	—		$	991
Deferred Annuities, Structured Settlements, And Other	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'
Fair Values of Deferred Annuities, Structured Settlements and Other Items	'
	The following table shows fair values of our deferred annuities and structured settlements, included in life policy and investment contract reserves, subject to fair value disclosure requirements:
	(In millions)		Quoted prices in			Significant other			Significant			Total
			active markets for			observable inputs			unobservable
			identical assets			(Level 2)			inputs
	At March 31, 2014		(Level 1)						(Level 3)
	Deferred annuities		$	—		$	—		$	900		$	900
	Structured settlements		—			212			—			212
	Total		$	—		$	212		$	900		$	1,112
	At December 31, 2013
	Deferred annuities		$	—		$	—		$	911		$	911
	Structured settlements		—			219			—			219
	Total		$	—		$	219		$	911		$	1,130

Property_Casualty_Loss_and_Los1

Property Casualty Loss and Loss Expenses (Tables)	3 Months Ended
	Mar. 31, 2014
Premiums Written, Net [Abstract]	'
Consolidated Property Casualty Loss And Loss Expense Reserves	'
	This table summarizes activity for our consolidated property casualty loss and loss expense reserves:
	(In millions)	Three months ended March 31,
		2014			2013
	Gross loss and loss expense reserves, beginning of period	$	4,241		$	4,169
	Less reinsurance receivable	299			356
	Net loss and loss expense reserves, beginning of period	3,942			3,813
	Net incurred loss and loss expenses related to:
	Current accident year	705			534
	Prior accident years	(29		)	(10		)
	Total incurred	676			524
	Net paid loss and loss expenses related to:
	Current accident year	197			121
	Prior accident years	387			392
	Total paid	584			513
	Net loss and loss expense reserves, end of period	4,034			3,824
	Plus reinsurance receivable	289			349
	Gross loss and loss expense reserves, end of period	$	4,323		$	4,173

Life_Policy_and_Investment_Con1

Life Policy and Investment Contract Reserves (Tables)	3 Months Ended
	Mar. 31, 2014
Liability for Future Policy Benefits [Abstract]	'
Reserve For Losses Loss Adjustment Expenses Table [Text Block]	'
	This table summarizes our life policy and investment contract reserves:
	(In millions)	March 31,		December 31, 2013
		2014
	Ordinary/traditional life	$	830	$	815
	Universal life	509		508
	Deferred annuities	864		862
	Structured settlements	187		189
	Other	45		16
	Total life policy and investment contract reserves	$	2,435	$	2,390

Deferred_Acquisition_Costs_Tab

Deferred Acquisition Costs (Tables)	3 Months Ended
	Mar. 31, 2014
Deferred Costs [Abstract]	'
Deferred Policy Acquisition Costs And Asset Reconciliation, Including the Amortized Deferred Policy Acquisition Costs	'
	The table below shows the deferred policy acquisition costs and asset reconciliation.
	(In millions)	Three months ended March 31,
		2014			2013
	Deferred policy acquisition costs asset, beginning of period	$	565		$	470
	Capitalized deferred policy acquisition costs	206			198
	Amortized deferred policy acquisition costs	(201		)	(179		)
	Amortized shadow deferred policy acquisition costs	(6		)	2
	Deferred policy acquisition costs asset, end of period	$	564		$	491

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	3 Months Ended
	Mar. 31, 2014
Accumulated Other Comprehensive Income [Abstract]	'
Schedule of Accumulated Other Comprehensive Income (Loss)	'
	(In millions)	Three months ended March 31,
		2014									2013
		Before tax			Income tax			Net			Before tax			Income tax			Net
	Accumulated unrealized gains, net, on investments available for sale,	$	2,335		$	808		$	1,527		$	1,875		$	647		$	1,228
	beginning of period
	Other comprehensive income before reclassification	135			48			87			397			139			258
	Reclassification adjustment for realized investment gains, net,	(18		)	(7		)	(11		)	(41		)	(15		)	(26		)
	included in net income
	Effect on other comprehensive income	117			41			76			356			124			232
	Accumulated unrealized gains, net, on investments available for sale,	$	2,452		$	849		$	1,603		$	2,231		$	771		$	1,460
	end of period
	Accumulated unrealized losses, net, for pension obligations,	$	(18	)	$	(6	)	$	(12	)	$	(101	)	$	(35	)	$	(66	)
	beginning of period
	Effect on other comprehensive income	(1		)	—			(1		)	2			1			1
	Accumulated unrealized losses, net, for pension obligations,	$	(19	)	$	(6	)	$	(13	)	$	(99	)	$	(34	)	$	(65	)
	end of period
	Accumulated unrealized losses, net, on life deferred acquisition costs,	$	(16	)	$	(5	)	$	(11	)	$	(50	)	$	(17	)	$	(33	)
	life policy reserves and other, beginning of period
	Other comprehensive income before reclassification	3			1			2			—			—			—
	Reclassification adjustment for life deferred acquisition costs,	(4		)	(1		)	(3		)	—			—			—
	life policy reserves and other, net, included in net income
	Effect on other comprehensive income	(1		)	—			(1		)	—			—			—
	Accumulated unrealized losses, net, on life deferred acquisition costs,	$	(17	)	$	(5	)	$	(12	)	$	(50	)	$	(17	)	$	(33	)
	life policy reserves and other, end of period
	Accumulated other comprehensive income, beginning of period	$	2,301		$	797		$	1,504		$	1,724		$	595		$	1,129
	Change in unrealized gains, net, on investments available for sale	117			41			76			356			124			232
	Change in pension obligations	(1		)	—			(1		)	2			1			1
	Change in life deferred acquisition costs, life policy reserves	(1		)	—			(1		)	—			—			—
	and other
	Effect on other comprehensive income	115			41			74			358			125			233
	Accumulated other comprehensive income, end of period	$	2,416		$	838		$	1,578		$	2,082		$	720		$	1,362

Reinsurance_Tables

Reinsurance (Tables)	3 Months Ended
	Mar. 31, 2014
Reinsurance Disclosures [Abstract]	'
Earned Consolidated Property Casualty Insurance Premiums On Assumed And Ceded Business	'
	Our condensed consolidated statements of income include earned consolidated property casualty insurance premiums on assumed and ceded business:
	(In millions)	Three months ended March 31,
		2014			2013
	Direct earned premiums	$	1,019		$	935
	Assumed earned premiums	3			2
	Ceded earned premiums	(43		)	(48		)
	Net earned premiums	$	979		$	889
Incurred Consolidated Property Casualty Insurance Loss And Loss Expenses On Assumed And Ceded Business	'
	Our condensed consolidated statements of income include incurred consolidated property casualty insurance loss and loss expenses on assumed and ceded business:
	(In millions)	Three months ended March 31,
		2014			2013
	Direct incurred loss and loss expenses	$	677		$	535
	Assumed incurred loss and loss expenses	2			2
	Ceded incurred loss and loss expenses	(3		)	(13		)
	Net incurred loss and loss expenses	$	676		$	524
Earned Life Insurance Premiums On Ceded Business	'
	Our condensed consolidated statements of income include earned life insurance premiums on ceded business:
	(In millions)	Three months ended March 31,
		2014			2013
	Direct earned premiums	$	62		$	56
	Ceded earned premiums	(14		)	(14		)
	Net earned premiums	$	48		$	42
Life Insurance Contract Holders' Benefits Incurred On Ceded Business	'
	Our condensed consolidated statements of income include life insurance policyholders’ benefits incurred on ceded business:
	(In millions)	Three months ended March 31,
		2014			2013
	Direct policyholders' benefits incurred	$	80		$	64
	Ceded policyholders' benefits incurred	(24		)	(20		)
	Net policyholders' benefits incurred	$	56		$	44

Income_Taxes_Tables

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2014
Income Tax Disclosure [Abstract]	'
Differences Between The 35 Percent Statutory Income Tax Rate And Effective Income Tax Rate	'
	The differences between the 35 percent statutory income tax rate and our effective income tax rate were as follows:
	(In millions)	Three months ended March 31,
		2014					2013
	Tax at statutory rate	$	42		35	%	$	76		35	%
	Increase (decrease) resulting from:
	Tax-exempt income from municipal bonds	(8		)	(6.7	)	(8		)	(3.7	)
	Dividend received exclusion	(7		)	(5.9	)	(6		)	(2.6	)
	Other	1			1.1		1			0.3
	Provision for income taxes	$	28		23.5	%	$	63		29	%

Net_Income_Per_Common_Share_Ta

Net Income Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Calculations For Basic And Diluted Earnings Per Share	'
	The table shows calculations for basic and diluted earnings per share:
	(In millions except per share data)	Three months ended March 31,
		2014		2013
	Numerator:
	Net income—basic and diluted	$	91	$	154
	Denominator:
	Basic weighted-average common shares outstanding	163.4		163.1
	Effect of stock-based awards:
	Stock options	1		1
	Nonvested shares	0.6		0.8
	Adjusted diluted weighted-average shares	165		164.9
	Earnings per share:
	Basic	$	0.56	$	0.95
	Diluted	0.55		0.94
	Number of anti-dilutive stock-based awards	0.7		2.1

Employee_Retirement_Benefits_T

Employee Retirement Benefits (Tables)	3 Months Ended
	Mar. 31, 2014
Compensation and Retirement Disclosure [Abstract]	'
Schedule of Defined Benefit Plans Disclosures	'
	The following summarizes the components of net periodic costs for our qualified and supplemental pension plans:
	(In millions)	Three months ended March 31,
		2014			2013
	Service cost	$	2		$	3
	Interest cost	4			3
	Expected return on plan assets	(4		)	(4		)
	Amortization of actuarial loss and prior service cost	1			2
	Net periodic benefit cost	$	3		$	4

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segment Information	'
	Segment information is summarized in the following table:
	(In millions)	Three months ended March 31,
		2014			2013
	Revenues:
	Commercial lines insurance
	Commercial casualty	$	224		$	204
	Commercial property	171			147
	Commercial auto	126			114
	Workers' compensation	92			88
	Specialty packages	36			39
	Management liability and surety	31			29
	Machinery and equipment	12			10
	Commercial lines insurance premiums	692			631
	Fee revenue	1			—
	Total commercial lines insurance	693			631
	Personal lines insurance
	Personal auto	116			107
	Homeowner	109			96
	Other personal lines	29			28
	Personal lines insurance premiums	254			231
	Excess and surplus lines insurance	33			27
	Life insurance premiums	48			42
	Separate account investment management fees	2			1
	Total life insurance	50			43
	Investment operations
	Investment income, net of expenses	135			128
	Realized investment gains, net	22			41
	Total investment revenue	157			169
	Other	2			2
	Total revenues	$	1,189		$	1,103
	Income (loss) before income taxes:
	Insurance underwriting results
	Commercial lines insurance	$	2		$	58
	Personal lines insurance	(7		)	20
	Excess and surplus lines insurance	4			—
	Life insurance	—			7
	Investment operations	136			148
	Other	(16		)	(16		)
	Total income before income taxes	$	119		$	217
	Identifiable assets:	March 31,			December 31, 2013
		2014
	Property casualty insurance	$	2,493		$	2,455
	Life insurance	1,302			1,225
	Investment operations	13,730			13,618
	Other	417			364
	Total	$	17,942		$	17,662

Investments_Analysis_of_Cost_o

Investments - Analysis of Cost or Amortized Cost, Gross Unrealized Gains and Losses and Fair Value for Investments (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Debt Securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost or Amortized Cost	$8,609	$8,638
Gross Unrealized Gains	613	558
Gross Unrealized Losses	42	75
Fair Value	9,180	9,121
Debt Securities | States, Municipalities And Political Subdivisions	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost or Amortized Cost	3,113	3,107
Gross Unrealized Gains	143	125
Gross Unrealized Losses	12	21
Fair Value	3,244	3,211
Debt Securities | Convertibles And Bonds With Warrants Attached	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost or Amortized Cost	17	17
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	17	17
Debt Securities | United States Government	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost or Amortized Cost	7	7
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	7	7
Debt Securities | Government-Sponsored Enterprises	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost or Amortized Cost	211	227
Gross Unrealized Gains	0	0
Gross Unrealized Losses	20	27
Fair Value	191	200
Debt Securities | Foreign Government	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost or Amortized Cost	10	10
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	10	10
Debt Securities | Commercial Mortgage Backed Securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost or Amortized Cost	206	148
Gross Unrealized Gains	2	0
Gross Unrealized Losses	2	5
Fair Value	206	143
Debt Securities | Corporate Securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost or Amortized Cost	5,045	5,122
Gross Unrealized Gains	468	433
Gross Unrealized Losses	8	22
Fair Value	5,505	5,533
Equity Securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost or Amortized Cost	2,545	2,523
Gross Unrealized Gains	1,888	1,856
Gross Unrealized Losses	7	4
Fair Value	4,426	4,375
Equity Securities | Common Stock	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost or Amortized Cost	2,418	2,396
Gross Unrealized Gains	1,845	1,818
Gross Unrealized Losses	6	1
Fair Value	4,257	4,213
Equity Securities | Preferred Stock	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost or Amortized Cost	127	127
Gross Unrealized Gains	43	38
Gross Unrealized Losses	1	3
Fair Value	169	162
Fixed Maturities And Equity Securities	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Cost or Amortized Cost	11,154	11,161
Gross Unrealized Gains	2,501	2,414
Gross Unrealized Losses	49	79
Fair Value	$13,606	$13,496

Investments_Fair_Values_and_Un

Investments - Fair Values and Unrealized Losses by Investment Category and by Duration of Securities' Continuous Unrealized Loss Position (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Investments, Unrealized Loss Position [Line Items]	'	'
Less than 12 months Fair Value	$840,000,000	$1,516,000,000
Less than 12 months Unrealized Losses	30,000,000	74,000,000
12 months or more Fair Value	274,000,000	86,000,000
12 months or more Unrealized Losses	19,000,000	5,000,000
Total Fair Value	1,114,000,000	1,602,000,000
Total Unrealized Losses	49,000,000	79,000,000
Fixed Maturities	'	'
Investments, Unrealized Loss Position [Line Items]	'	'
Less than 12 months Fair Value	729,000,000	1,397,000,000
Less than 12 months Unrealized Losses	23,000,000	70,000,000
12 months or more Fair Value	274,000,000	86,000,000
12 months or more Unrealized Losses	19,000,000	5,000,000
Total Fair Value	1,003,000,000	1,483,000,000
Total Unrealized Losses	42,000,000	75,000,000
Fixed Maturities | States, Municipalities And Political Subdivisions	'	'
Investments, Unrealized Loss Position [Line Items]	'	'
Less than 12 months Fair Value	289,000,000	490,000,000
Less than 12 months Unrealized Losses	7,000,000	18,000,000
12 months or more Fair Value	98,000,000	42,000,000
12 months or more Unrealized Losses	5,000,000	3,000,000
Total Fair Value	387,000,000	532,000,000
Total Unrealized Losses	12,000,000	21,000,000
Fixed Maturities | United States Government	'	'
Investments, Unrealized Loss Position [Line Items]	'	'
Less than 12 months Fair Value	11,000,000	1,000,000
Less than 12 months Unrealized Losses	0	0
12 months or more Fair Value	0	0
12 months or more Unrealized Losses	0	0
Total Fair Value	11,000,000	1,000,000
Total Unrealized Losses	0	0
Fixed Maturities | Government-Sponsored Enterprises	'	'
Investments, Unrealized Loss Position [Line Items]	'	'
Less than 12 months Fair Value	83,000,000	199,000,000
Less than 12 months Unrealized Losses	8,000,000	27,000,000
12 months or more Fair Value	96,000,000	1,000,000
12 months or more Unrealized Losses	12,000,000	0
Total Fair Value	179,000,000	200,000,000
Total Unrealized Losses	20,000,000	27,000,000
Fixed Maturities | Commercial Mortgage Backed Securities	'	'
Investments, Unrealized Loss Position [Line Items]	'	'
Less than 12 months Fair Value	55,000,000	'
Less than 12 months Unrealized Losses	1,000,000	'
12 months or more Fair Value	15,000,000	'
12 months or more Unrealized Losses	1,000,000	'
Total Fair Value	70,000,000	'
Total Unrealized Losses	2,000,000	'
Fixed Maturities | Corporate Securities	'	'
Investments, Unrealized Loss Position [Line Items]	'	'
Less than 12 months Fair Value	291,000,000	572,000,000
Less than 12 months Unrealized Losses	7,000,000	20,000,000
12 months or more Fair Value	65,000,000	43,000,000
12 months or more Unrealized Losses	1,000,000	2,000,000
Total Fair Value	356,000,000	615,000,000
Total Unrealized Losses	8,000,000	22,000,000
Equity Securities	'	'
Investments, Unrealized Loss Position [Line Items]	'	'
Less than 12 months Fair Value	111,000,000	119,000,000
Less than 12 months Unrealized Losses	7,000,000	4,000,000
12 months or more Fair Value	0	0
12 months or more Unrealized Losses	500,000,000	0
Total Fair Value	111,000,000	119,000,000
Total Unrealized Losses	7,000,000	4,000,000
Equity Securities | Common Stock	'	'
Investments, Unrealized Loss Position [Line Items]	'	'
Less than 12 months Fair Value	72,000,000	77,000,000
Less than 12 months Unrealized Losses	6,000,000	1,000,000
12 months or more Fair Value	0	'
Total Fair Value	72,000,000	77,000,000
Total Unrealized Losses	6,000,000	1,000,000
Equity Securities | Preferred Stock	'	'
Investments, Unrealized Loss Position [Line Items]	'	'
Less than 12 months Fair Value	39,000,000	42,000,000
Less than 12 months Unrealized Losses	1,000,000	3,000,000
12 months or more Fair Value	0	0
12 months or more Unrealized Losses	'	0
Total Fair Value	39,000,000	42,000,000
Total Unrealized Losses	$1,000,000	$3,000,000

Investments_Realized_Investmen

Investments - Realized Investment Gains and Losses and Change in Unrealized Investment Gains and Losses and Other Items (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Investment income summary:	'	'
Interest on fixed maturities	$104	$102
Dividends on equity securities	32	27
Other investment income	1	1
Total	137	130
Less investment expenses	2	2
Total	135	128
Realized investment gains and losses summary:	'	'
Other	2	-3
Realized gains on investments	22	41
Change in unrealized gains and losses summary:	'	'
Unrealized gains (losses) on investments available-for-sale	76	232
Adjustment to deferred acquisition costs and life policy reserves	-3	3
Amortization of pension actuarial loss and prior service cost	-1	2
Other	2	-3
Income taxes on above	41	125
Other comprehensive income (loss), net of tax	74	233
Fixed Maturities	'	'
Realized investment gains and losses summary:	'	'
Gross realized gains	2	2
Gross realized losses	0	0
Other-than-temporary impairments	0	-2
Change in unrealized gains and losses summary:	'	'
Unrealized gains (losses) on investments available-for-sale	88	-25
Equity Securities	'	'
Realized investment gains and losses summary:	'	'
Gross realized gains	18	37
Gross realized losses	0	0
Other-than-temporary impairments	-1	0
Securities with embedded derivatives	-1	1
Other	4	3
Change in unrealized gains and losses summary:	'	'
Unrealized gains (losses) on investments available-for-sale	29	381
Other	$4	$3

Investments_Additional_Informa

Investments - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Gain (Loss) on Investments [Line Items]	'	'
Fixed maturities, fair value of hybrid securities	$17,000,000	$18,000,000
Unrealized losses 12 months or more (equity investment less than $500,000)	19,000,000	5,000,000
Fixed maturity investments, Percentage of amortized costs	70.00%	70.00%
Fixed Maturities	'	'
Gain (Loss) on Investments [Line Items]	'	'
Number Of Securities Other Than Temporary Impairment Losses	1	7
Number Of Securities Continuous Unrealized Loss Position More Than Twelve Months	99	40
Unrealized investment gains due to a net gain position	613,000,000	558,000,000
Unrealized losses 12 months or more (equity investment less than $500,000)	19,000,000	5,000,000
Equity Securities	'	'
Gain (Loss) on Investments [Line Items]	'	'
Number Of Securities Other Than Temporary Impairment Losses	2	'
Number Of Securities Continuous Unrealized Loss Position More Than Twelve Months	1	'
Unrealized investment gains due to a net gain position	1,888,000,000	1,856,000,000
Unrealized losses 12 months or more (equity investment less than $500,000)	500,000,000	0
Procter And Gamble Company, Exxon Mobile Corporation And Chevron Corporation [Member]	'	'
Gain (Loss) on Investments [Line Items]	'	'
Unrealized investment gains due to a net gain position	$431,000,000	'
Common Stock	'	'
Gain (Loss) on Investments [Line Items]	'	'
Number of securities	5	'

Fair_Value_Measurements_Fair_V

Fair Value Measurements - Fair Value Hierarchy for Assets Measured at Fair Value on Recurring Basis (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	$9,180	$9,121
Equity securities, at fair value	4,426	4,375
Separate accounts	725	692
Fair value of asset	14,323	14,192
Top Hat Savings Plan	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Other investments	17	14
Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	9,180	9,121
Debt Securities | States, Municipalities And Political Subdivisions	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	3,244	3,211
Debt Securities | Convertibles And Bonds With Warrants Attached	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	17	17
Debt Securities | United States Government	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	7	7
Debt Securities | Government-Sponsored Enterprises	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	191	200
Debt Securities | Foreign Government	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	10	10
Debt Securities | Commercial Mortgage Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	206	143
Debt Securities | Corporate Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	5,505	5,533
Equity Securities | Common Stock	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities, at fair value	4,257	4,213
Equity Securities | Preferred Stock	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities, at fair value	169	162
Taxable Fixed Maturities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Separate accounts	700	682
Quoted prices in active markets for identical assets (Level 1)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of asset	4,281	4,234
Quoted prices in active markets for identical assets (Level 1) | Top Hat Savings Plan	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Other investments	17	14
Quoted prices in active markets for identical assets (Level 1) | Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	7	7
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | States, Municipalities And Political Subdivisions	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | Convertibles And Bonds With Warrants Attached	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | United States Government	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	7	7
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | Government-Sponsored Enterprises	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | Foreign Government	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | Commercial Mortgage Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | Corporate Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Equity Securities | Common Stock	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities, at fair value	4,257	4,213
Quoted prices in active markets for identical assets (Level 1) | Equity Securities | Preferred Stock	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Taxable Fixed Maturities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Separate accounts	0	0
Significant other observable inputs (Level 2)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of asset	10,027	9,954
Significant other observable inputs (Level 2) | Top Hat Savings Plan	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Other investments	0	0
Significant other observable inputs (Level 2) | Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	9,160	9,112
Significant other observable inputs (Level 2) | Debt Securities | States, Municipalities And Political Subdivisions	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	3,244	3,211
Significant other observable inputs (Level 2) | Debt Securities | Convertibles And Bonds With Warrants Attached	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	17	17
Significant other observable inputs (Level 2) | Debt Securities | United States Government	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	0	0
Significant other observable inputs (Level 2) | Debt Securities | Government-Sponsored Enterprises	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	191	200
Significant other observable inputs (Level 2) | Debt Securities | Foreign Government	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	10	10
Significant other observable inputs (Level 2) | Debt Securities | Commercial Mortgage Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	201	143
Significant other observable inputs (Level 2) | Debt Securities | Corporate Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	5,497	5,531
Significant other observable inputs (Level 2) | Equity Securities | Common Stock	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities, at fair value	0	0
Significant other observable inputs (Level 2) | Equity Securities | Preferred Stock	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities, at fair value	167	160
Significant other observable inputs (Level 2) | Taxable Fixed Maturities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Separate accounts	700	682
Significant unobservable inputs (Level 3)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of asset	15	4
Significant unobservable inputs (Level 3) | Top Hat Savings Plan	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Other investments	0	0
Significant unobservable inputs (Level 3) | Debt Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	13	2
Significant unobservable inputs (Level 3) | Debt Securities | States, Municipalities And Political Subdivisions	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	0	0
Significant unobservable inputs (Level 3) | Debt Securities | Convertibles And Bonds With Warrants Attached	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	0	0
Significant unobservable inputs (Level 3) | Debt Securities | United States Government	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	0	0
Significant unobservable inputs (Level 3) | Debt Securities | Government-Sponsored Enterprises	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	0	0
Significant unobservable inputs (Level 3) | Debt Securities | Foreign Government	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	0	0
Significant unobservable inputs (Level 3) | Debt Securities | Commercial Mortgage Backed Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	5	0
Significant unobservable inputs (Level 3) | Debt Securities | Corporate Securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fixed maturities, at fair value	8	2
Significant unobservable inputs (Level 3) | Equity Securities | Common Stock	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities, at fair value	0	0
Significant unobservable inputs (Level 3) | Equity Securities | Preferred Stock	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Equity securities, at fair value	2	2
Significant unobservable inputs (Level 3) | Taxable Fixed Maturities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Separate accounts	$0	$0

Fair_Value_Measurements_Change

Fair Value Measurements - Change in Level 3 Assets (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Beginning balance	$4	$5
Total gains or losses (realized/unrealized):	'	'
Included in earnings (or changes in net assets)	0	0
Included in other comprehensive income	0	0
Purchases	0	1
Sales	0	0
Transfers into Level 3	11	0
Transfers out of Level 3	0	0
Ending balance	15	6
Corporate Fixed Maturities	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Beginning balance	2	3
Total gains or losses (realized/unrealized):	'	'
Included in earnings (or changes in net assets)	0	0
Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Transfers into Level 3	6	0
Transfers out of Level 3	0	0
Ending balance	8	3
Commercial Mortgage Backed Securities	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Beginning balance	0	0
Total gains or losses (realized/unrealized):	'	'
Included in earnings (or changes in net assets)	0	0
Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Transfers into Level 3	5	0
Transfers out of Level 3	0	0
Ending balance	5	0
States, Municipalities And Political Subdivisions Fixed Maturities	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Beginning balance	0	1
Total gains or losses (realized/unrealized):	'	'
Included in earnings (or changes in net assets)	0	0
Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	0	1
Preferred Equities	'	'
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]	'	'
Beginning balance	2	1
Total gains or losses (realized/unrealized):	'	'
Included in earnings (or changes in net assets)	0	0
Included in other comprehensive income	0	0
Purchases	0	1
Sales	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	$2	$2

Fair_Value_Measurements_Summar

Fair Value Measurements - Summary of Book Value and Principal Amounts of Long-Term Debt (Detail) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]	'	'
Book value	$790	$790
Principal amount of debt	793	793
Senior Debentures 6.900% Due 2028	'	'
Debt Instrument [Line Items]	'	'
Interest rate	6.90%	6.90%
Debt issuance year	'1998	'1998
Book value	28	28
Principal amount of debt	28	28
Senior Debentures 6.920% Due 2028	'	'
Debt Instrument [Line Items]	'	'
Interest rate	6.92%	6.92%
Debt issuance year	'2005	'2005
Book value	391	391
Principal amount of debt	391	391
Senior Notes 6.152% Due 2034	'	'
Debt Instrument [Line Items]	'	'
Interest rate	6.13%	6.13%
Debt issuance year	'2004	'2004
Book value	371	371
Principal amount of debt	$374	$374

Fair_Value_Measurements_Fair_V1

Fair Value Measurements - Fair Values of Note Payable and Long-Term Debt (Detail) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of note payable	$104	$104
Total	1,025	991
Senior Debentures 6.900 % Due 2028	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Interest rate	6.90%	6.90%
Debt instrument, year of maturity	'2028	'2028
Fair value of senior debt	32	30
Senior Debentures 6.920 % Due 2028	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Interest rate	6.92%	6.92%
Debt instrument, year of maturity	'2028	'2028
Fair value of senior debt	470	458
Senior Notes 6.125 % Due 2034	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Interest rate	6.13%	6.13%
Debt instrument, year of maturity	'2034	'2034
Fair value of senior debt	419	399
Quoted prices in active markets for identical assets (Level 1)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of note payable	0	0
Total	0	0
Quoted prices in active markets for identical assets (Level 1) | Senior Debentures 6.900 % Due 2028	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of senior debt	0	0
Quoted prices in active markets for identical assets (Level 1) | Senior Debentures 6.920 % Due 2028	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of senior debt	0	0
Quoted prices in active markets for identical assets (Level 1) | Senior Notes 6.125 % Due 2034	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of senior debt	0	0
Significant other observable inputs (Level 2)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of note payable	104	104
Total	1,025	991
Significant other observable inputs (Level 2) | Senior Debentures 6.900 % Due 2028	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of senior debt	32	30
Significant other observable inputs (Level 2) | Senior Debentures 6.920 % Due 2028	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of senior debt	470	458
Significant other observable inputs (Level 2) | Senior Notes 6.125 % Due 2034	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of senior debt	419	399
Significant unobservable inputs (Level 3)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of note payable	0	0
Total	0	0
Significant unobservable inputs (Level 3) | Senior Debentures 6.900 % Due 2028	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of senior debt	0	0
Significant unobservable inputs (Level 3) | Senior Debentures 6.920 % Due 2028	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of senior debt	0	0
Significant unobservable inputs (Level 3) | Senior Notes 6.125 % Due 2034	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of senior debt	$0	$0

Fair_Value_Measurements_Fair_V2

Fair Value Measurements - Fair Value of Life Policy Loans (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of life policy loans	$44	$45
Quoted prices in active markets for identical assets (Level 1)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of life policy loans	0	0
Significant other observable inputs (Level 2)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of life policy loans	0	0
Significant unobservable inputs (Level 3)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of life policy loans	$44	$45

Fair_Value_Measurements_Fair_V3

Fair Value Measurements - Fair Values of Deferred Annuities, Structured Settlements and Other Items (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair Value of life insurance liabilities	$1,112	$1,130
Deferred Annuities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair Value of life insurance liabilities	900	911
Structured Settlements	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair Value of life insurance liabilities	212	219
Quoted prices in active markets for identical assets (Level 1)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair Value of life insurance liabilities	0	0
Quoted prices in active markets for identical assets (Level 1) | Deferred Annuities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair Value of life insurance liabilities	0	0
Quoted prices in active markets for identical assets (Level 1) | Structured Settlements	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair Value of life insurance liabilities	0	0
Significant other observable inputs (Level 2)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair Value of life insurance liabilities	212	219
Significant other observable inputs (Level 2) | Deferred Annuities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair Value of life insurance liabilities	0	0
Significant other observable inputs (Level 2) | Structured Settlements	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair Value of life insurance liabilities	212	219
Significant unobservable inputs (Level 3)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair Value of life insurance liabilities	900	911
Significant unobservable inputs (Level 3) | Deferred Annuities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair Value of life insurance liabilities	900	911
Significant unobservable inputs (Level 3) | Structured Settlements	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair Value of life insurance liabilities	$0	$0

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Finance receivable	$83	$85
Loss and loss expense reserves	4,375	4,311
Maximum	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Percentage of Level 3 assets measured at fair value	1.00%	'
Life Policy Loans	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Finance receivable	35	36
Deferred Annuities And Structured Settlements	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Loss and loss expense reserves	$1,051	'

Property_Casualty_Loss_and_Los2

Property Casualty Loss and Loss Expenses - Consolidated Property Casualty Loss and Loss Expense Reserves (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Summary of Consolidated Property Casualty Loss and Loss Expense Reserves [Roll Forward]	'	'
Gross loss and loss expense reserves, beginning of period	$4,241	$4,169
Less reinsurance receivable	299	356
Net loss and loss expense reserves, beginning of period	3,942	3,813
Current accident year	705	534
Prior accident years	-29	-10
Total incurred	676	524
Current accident year	197	121
Prior accident years	387	392
Total paid	584	513
Net loss and loss expense reserves, end of period	4,034	3,824
Plus reinsurance receivable	289	349
Gross loss and loss expense reserves, end of period	$4,323	$4,173

Property_Casualty_Loss_and_Los3

Property Casualty Loss and Loss Expenses - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]	'	'
Favorable reserve development on prior accident years	$29	$10
Life and Health Loss Reserves	'	'
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]	'	'
Reserve for loss and loss expenses	52	67
Commercial Lines	'	'
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]	'	'
Favorable reserve development on prior accident years	3	'
Personal Lines	'	'
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]	'	'
Favorable reserve development on prior accident years	17	'
Excess And Surplus Lines Insurance	'	'
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]	'	'
Favorable reserve development on prior accident years	9	'
Consolidated Property and Casualty Insurance Entity [Member] | Catastrophe Development	'	'
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]	'	'
Favorable reserve development on prior accident years	$9	$7

Reserves_in_Addition_to_Accoun

Reserves in Addition to Account Balance, Based on Expected No-Lapse Guarantee Benefits and Expected Policy Assessments (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Liability for Future Policy Benefit, by Product Segment [Line Items]	'	'
Life policy and investment contract reserves	$2,435	$2,390
Ordinary/Traditional Life	'	'
Liability for Future Policy Benefit, by Product Segment [Line Items]	'	'
Life policy and investment contract reserves	830	815
Universal Life	'	'
Liability for Future Policy Benefit, by Product Segment [Line Items]	'	'
Life policy and investment contract reserves	509	508
Deferred Annuities	'	'
Liability for Future Policy Benefit, by Product Segment [Line Items]	'	'
Life policy and investment contract reserves	864	862
Structured Settlements	'	'
Liability for Future Policy Benefit, by Product Segment [Line Items]	'	'
Life policy and investment contract reserves	187	189
Other	'	'
Liability for Future Policy Benefit, by Product Segment [Line Items]	'	'
Life policy and investment contract reserves	$45	$16

Deferred_Acquisition_Costs_Def

Deferred Acquisition Costs - Deferred Policy Acquisition Costs and Asset Reconciliation (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]	'	'
Deferred policy acquisition costs asset, beginning of period	$565	$470
Capitalized deferred policy acquisition costs	206	198
Amortized deferred policy acquisition costs	-201	-179
Amortized shadow deferred policy acquisition costs	-6	2
Deferred policy acquisition costs asset, end of period	$564	$491

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'	'	'	'
Accumulated other comprehensive income, net of tax, beginning of period	$1,578	'	$1,504	'
Accumulated other comprehensive income, net of tax, end of period	1,578	'	1,504	'
Accumulated Net Unrealized Investment Gain (Loss)	'	'	'	'
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]	'	'	'	'
Accumulated unrealized gains, net, on investments available for sale, before tax, beginning of period	2,335	1,875	'	'
Other comprehensive income before reclassification, before tax	135	397	'	'
Reclassification adjustment for realized gains, net, included in net income, before tax	-18	-41	'	'
Effect on other comprehensive income, before tax	117	356	'	'
Accumulated unrealized gains, net, on investments available for sale, before tax, end of period	2,452	2,231	'	'
Accumulated Other Comprehensive Income Loss Tax [Abstract]	'	'	'	'
Accumulated unrealized gains, net, on investments available for sale and other invested assets, tax, beginning of period	849	771	'	'
Other comprehensive income before reclassification, tax	48	139	'	'
Reclassification adjustment for realized gains, net, included in net income, tax	-7	-15	'	'
Effect on other comprehensive income, tax	41	124	'	'
Accumulated unrealized gains, net, on investments available for sale and other invested assets, tax, end of period	808	647	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'	'	'	'
Accumulated unrealized gains, net, on investments available for sale and other invested assets, net of tax, beginning of period	1,527	1,228	'	'
Other comprehensive income before reclassification , net of tax	87	258	'	'
Reclassification adjustment for realized gains, net, included in net income, net of tax	-11	-26	'	'
Effect on other comprehensive income, net of tax	76	232	'	'
Accumulated unrealized gains, net, on investments available for sale and other invested assets, net of tax, end of period	1,603	1,460	'	'
Accumulated Defined Benefit Plans Adjustment	'	'	'	'
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]	'	'	'	'
Accumulated unrealized losses, net, for pension obligations, before Tax, beginning of period	-18	-101	'	'
Effect on other comprehensive income, before tax	-1	2	'	'
Accumulated unrealized losses, net, for pension obligations, before Tax, end of period	-19	-99	'	'
Accumulated Other Comprehensive Income Loss Tax [Abstract]	'	'	'	'
Accumulated unrealized losses, net, for pension obligations, tax, beginning of period	-6	-35	'	'
Effect on other comprehensive income, tax	0	1	'	'
Accumulated unrealized losses, net, for pension obligations, tax, end of period	-6	-34	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'	'	'	'
Accumulated unrealized losses, net, for pension obligations, net of tax, beginning of period	-12	-66	'	'
Effect on other comprehensive income, net of tax	-1	1	'	'
Accumulated unrealized losses, net, for pension obligations, net of tax, end of period	-13	-65	'	'
Accumulated Net Unrealized Gain (Loss) on Deferred Costs, Reserves And Other	'	'	'	'
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]	'	'	'	'
Other comprehensive income before reclassification, before tax	3	0	'	'
Other Comprehensive Income (Loss), Reclassification Adjustment for Life Deferred Acquisition Costs, Life Policy Reserves and Other, Before Tax	-4	0	'	'
Accumulated unrealized losses, net, on life deferred acquisition costs, life policy reserves and other, before tax, beginning of period	-16	-50	'	'
Effect on other comprehensive income, before tax	-1	0	'	'
Accumulated unrealized losses, net, on life deferred acquisition costs, life policy reserves and other, before tax, end of period	-17	-50	'	'
Accumulated Other Comprehensive Income Loss Tax [Abstract]	'	'	'	'
Other comprehensive income before reclassification, tax	1	0	'	'
Accumulated unrealized losses, net, on life deferred acquisition costs, life policy reserves and other, tax, beginning of period	-5	-17	'	'
Other Comprehensive Income (Loss), Reclassification Adjustment for Life Deferred Acquisition Costs, Life Policy Reserves and Other, Tax	-1	0	'	'
Effect on other comprehensive income, tax	0	0	'	'
Accumulated unrealized losses, net, on life deferred acquisition costs, life policy reserves and other, tax, end of period	-5	-17	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'	'	'	'
Other comprehensive income before reclassification , net of tax	2	0	'	'
Accumulated unrealized losses, net, on life deferred acquisition costs, life policy reserves and other, beginning of period, net of tax	-11	-33	'	'
Other Comprehensive Income (Loss), Reclassification Adjustment for Life Deferred Acquisition Costs, Life Policy Reserves and Other, Net of Tax	-3	0	'	'
Effect on other comprehensive income, net of tax	-1	0	'	'
Accumulated unrealized losses, net, on life deferred acquisition costs, life policy reserves and other, end of period, net of tax	-12	-33	'	'
Accumulated Other Comprehensive Income (Loss)	'	'	'	'
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]	'	'	'	'
Accumulated other comprehensive income, before taxes, beginning of period	2,301	1,724	'	'
Change in unrealized gains, net, on investments available for sale, before Tax	117	356	'	'
Change in pension obligations, before tax	-1	2	'	'
Change in life deferred acquisition costs, life policy reserves and other, before Tax	-1	0	'	'
Effect on other comprehensive income, before Tax	115	358	'	'
Accumulated other comprehensive income, before taxes, end of period	2,416	2,082	'	'
Accumulated Other Comprehensive Income Loss Tax [Abstract]	'	'	'	'
Accumulated other comprehensive income, tax, beginning of period	797	595	'	'
Change in unrealized gains, net, on investments available for sale and other invested assets, tax	41	124	'	'
Change in pension obligations, tax	0	1	'	'
Change in life deferred acquisition costs, life policy reserves and other, tax	0	0	'	'
Effect on other comprehensive income, tax	41	125	'	'
Accumulated other comprehensive income, tax, end of period	838	720	'	'
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]	'	'	'	'
Accumulated other comprehensive income, net of tax, beginning of period	1,578	1,362	1,504	1,129
Change in unrealized gains, net, on investments available for sale, net of tax	76	232	'	'
Change in pension obligations, net of tax	-1	1	'	'
Change in life deferred acquisition costs, life policy reserves and other, net of tax	-1	0	'	'
Effect on other comprehensive income, net of tax	74	233	'	'
Accumulated other comprehensive income, net of tax, end of period	$1,578	$1,362	$1,504	$1,129

Reinsurance_Earned_Consolidate

Reinsurance - Earned Consolidated Property Casualty Insurance Premiums on Assumed and Ceded Business (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Reinsurance Disclosures [Abstract]	'	'
Direct earned premiums	$1,019	$935
Assumed earned premiums	3	2
Ceded earned premiums	-43	-48
Net earned premiums	$979	$889

Reinsurance_Incurred_Consolida

Reinsurance - Incurred Consolidated Property Casualty Insurance Loss and Loss Expenses on Assumed and Ceded Business (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]	'	'
Net incurred loss and loss expenses	$732	$568
Property, Liability And Casualty Insurance Segment	'	'
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]	'	'
Direct incurred loss and loss expenses	677	535
Assumed incurred loss and loss expenses	2	2
Ceded incurred loss and loss expenses	-3	-13
Net incurred loss and loss expenses	$676	$524

Reinsurance_Earned_Life_Insura

Reinsurance - Earned Life Insurance Premiums on Ceded Business (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]	'	'
Direct earned premiums	$1,019	$935
Assumed earned premiums	3	2
Ceded earned premiums	-43	-48
Life Insurance Segment	'	'
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]	'	'
Direct earned premiums	62	56
Ceded earned premiums	-14	-14
Net earned premiums	$48	$42

Reinsurance_Life_Insurance_Con

Reinsurance - Life Insurance Contract Holders' Benefits Incurred on Ceded Business (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]	'	'
Assumed earned premiums	$3	$2
Net incurred loss and loss expenses	732	568
Life Insurance Segment	'	'
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]	'	'
Direct policyholders' benefits incurred	80	64
Ceded policyholders' benefits incurred	-24	-20
Net incurred loss and loss expenses	$56	$44

Income_Taxes_Differences_Betwe

Income Taxes - Differences Between 35 Percent Statutory Income Tax Rate and Effective Income Tax Rate (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Income Tax Disclosure [Abstract]	'	'
Tax at statutory rate	$42	$76
Increase (decrease) resulting from:	'	'
Tax-exempt income from municipal bonds	-8	-8
Dividend received exclusion	-7	-6
Other	1	1
Total provision for income taxes	$28	$63
Tax at statutory rate	35.00%	35.00%
Increase (decrease) resulting from:	'	'
Tax-exempt income from municipal bonds	-6.70%	-3.70%
Dividend received exclusion	-5.90%	-2.60%
Other	1.10%	0.30%
Provision for income taxes	23.50%	29.00%

Income_Taxes_Narrative_Details

Income Taxes (Narrative) (Details)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Income Tax Disclosure [Abstract]	'	'
Tax at statutory rate, percentage	35.00%	35.00%

Net_Income_Per_Common_Share_Ca

Net Income Per Common Share - Calculations for Basic and Diluted Earnings Per Share (Detail) (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Numerator:	'	'
Net income-basic and diluted	$91	$154
Denominator:	'	'
Weighted-average common shares outstanding (in shares)	163.4	163.1
Adjusted diluted weighted-average shares (in shares)	165	164.9
Earnings per share:	'	'
Basic (in USD per share)	$0.56	$0.95
Diluted (in USD per share)	$0.55	$0.94
Number of anti-dilutive stock-based awards (in shares)	0.7	2.1
Nonvested shares	'	'
Denominator:	'	'
Effect of stock-based awards (in shares)	0.6	0.8
Stock Options	'	'
Denominator:	'	'
Effect of stock-based awards (in shares)	1	1

Employee_Retirement_Benefits_C

Employee Retirement Benefits - Components of Net Periodic Costs for Qualified and Supplemental Pension Plans (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Compensation and Retirement Disclosure [Abstract]	'	'
Service cost	$2	$3
Interest cost	4	3
Expected return on plan assets	-4	-4
Amortization of actuarial loss and prior service cost	1	2
Net periodic benefit cost	$3	$4

Employee_Retirement_Benefits_A

Employee Retirement Benefits - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'
Matching contributions for 401(k) plan and Top Hat savings plan	$4	$3
Pension Contributions	5	'
Qualified Pension Plans [Member] | Future Period [Member]	'	'
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]	'	'
Expected contribution by employer for the remainder of the year	$0	'

Commitments_and_Contingent_Lia1

Commitments and Contingent Liabilities (Narrative) (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Estimate for which the risk of loss is more than remote but not probable	$1

Segment_Information_Detail

Segment Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]	'	'	'
Revenues	$1,189	$1,103	'
Net Investment Income	135	128	'
Realized gains on investments	22	41	'
Income (loss) before income taxes	119	217	'
Identifiable assets	17,942	'	17,662
Property Casualty Insurance Segment	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Identifiable assets	2,493	'	2,455
Commercial Lines	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	693	631	'
Income (loss) before income taxes	2	58	'
Commercial Lines | Commercial Casualty Segment	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	224	204	'
Commercial Lines | Commercial Property Segment	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	171	147	'
Commercial Lines | Commercial Auto Segment	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	126	114	'
Commercial Lines | Workers' Compensation	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	92	88	'
Commercial Lines | Specialty Packages	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	36	39	'
Commercial Lines | Management liability and surety	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	31	29	'
Commercial Lines | Machinery and Equipment	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	12	10	'
Commercial Lines | Commercial Lines Insurance Premiums	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	692	631	'
Commercial Lines | Other Fee Revenue	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	1	0	'
Personal Lines	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Income (loss) before income taxes	-7	20	'
Personal Lines | Personal Auto	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	116	107	'
Personal Lines | Home Owner Segment	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	109	96	'
Personal Lines | Other Personal Lines	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	29	28	'
Personal Lines | Commercial Lines Insurance Premiums	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	254	231	'
Excess And Surplus Lines Insurance	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	33	27	'
Income (loss) before income taxes	4	0	'
Life Insurance Segment	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	50	43	'
Income (loss) before income taxes	0	7	'
Identifiable assets	1,302	'	1,225
Life Insurance Segment | Life Insurance Excluding Account Investment Fees	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	48	42	'
Life Insurance Segment | Seperate Account Investment Management Fees	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	2	1	'
Investments Segment	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	157	169	'
Income (loss) before income taxes	136	148	'
Identifiable assets	13,730	'	13,618
Investments Segment | Investment Income, Net	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Net Investment Income	135	128	'
Investments Segment | Realized Investment Gains, Net	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Realized gains on investments	22	41	'
Other	'	'	'
Segment Reporting Information [Line Items]	'	'	'
Revenues	2	2	'
Income (loss) before income taxes	-16	-16	'
Identifiable assets	$417	'	$364

Segment_Information_Narrative_

Segment Information - Narrative (Details)	3 Months Ended
	Mar. 31, 2014
	segment
	industry
Segment Reporting [Abstract]	'
Number of Industries Operating In	2
Number of Reportable Segments	5